Re: Turning off HOT/Cleanup sometimes - Mailing list pgsql-hackers

From Andres Freund
Subject Re: Turning off HOT/Cleanup sometimes
Date
Msg-id 8e5dfcd2-800c-4998-8732-7fcb7aebc928@email.android.com
Whole thread Raw
In response to Re: Turning off HOT/Cleanup sometimes  (Simon Riggs <simon@2ndquadrant.com>)
Responses Re: Turning off HOT/Cleanup sometimes  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: Turning off HOT/Cleanup sometimes  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On September 19, 2014 10:16:35 PM CEST, Simon Riggs <simon@2ndquadrant.com> wrote:
>On 19 September 2014 13:04, Robert Haas <robertmhaas@gmail.com> wrote:
>
>> What I'm thinking about is that the smarts to enable pruning is all
>in
>> the executor nodes.  So anything that updates the catalog without
>> going through the executor will never be subject to pruning.  That
>> includes nearly all catalog-modifying code throughout the backend.
>
>Are you saying this is a problem or a benefit? (and please explain
>why).

I have no idea what Robert is thinking of, but I'd imagine its horrible for workloads with catalog bloat. Like ones
involvingtemp tables.
 

I generally have serious doubts about disabling it generally for read workloads. I imagine it e.g. will significantly
penalizeworkloads where its likely that a cleanup lock can't be acquired every time...
 

Andres

--- 
Please excuse brevity and formatting - I am writing this on my mobile phone.



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